Article written by Cosimo Simeone, Msc, PgdDip, Bsc, Physiotherapist

How many times have you been to a chiropractor, osteopath or physiotherapist and you received spine or joints manipulations and you were guessing how these are really effective, safe or for what they are useful?  Today I will go through some evidence based research that shows what they are useful for and if there is any contraindications or any evidence of previous patients who had issues after this treatment.  


The scientific name of these manipulations is High-Velocity Low Amplitude (HVLA) manipulations techniques, which employ a rapid use of force over a short duration, distance, and/or rotational area within the anatomical range of motion of a joint to engage the restrictive barrier in one or more planes of motion to elicit the release of restriction. So these manipulation techniques use high velocity and low amplitude thrusts to manipulate joints. Moreover, HVLA strategies aim to re-establish normal joint operations. A physiological barrier is a point at which soft tissue stress restricts the voluntary range of movement in an articulation. Consequently, the velocity of the manipulative motion initiated the absorption of nitrogen, converting it from a liquid state to a gaseous one, and restoring the joint’s articulation.; this indicates that the range of motion is increased by cavitation. 

Science Behind the “Crack Sound”:

In brief, carbon dioxide is dispersed by cavitation which leads to audible joint pop. Following this the vasodilatory effects of carbon dioxide promote increased blood flow, chemotaxis, and cell-attaining nutrients. The joint’s popping often follows a manipulative motion. Crack noise or joint cavitation results from a gaseous bubble in the synovial fluid producing or collapsing. There are several hypotheses from a physiological perspective as to why HVLA is an efficient method of care. First, an HVLA thrust tends to stretch a contracted muscle, which, in turn, creates many afferent impulses to the central nervous system from the muscle spindles. The central nervous system then reflexively sends an inhibitory impulsion to the muscle spindle to relax the muscle. An alternative hypothesis suggests that the Golgi tendon receptors become activated instead of the muscle spindle, eventually relaxing the muscle (1). 

Indications & Contraindications:

The HVLA are indicated for Hypomobility of the Spine and all of the joints, Headaches and Migraine, Stress and Anxiety, Muscles Stiffness, Posture Abnormalities. HVLA therapy used in the cervical region may be effective in resolving the neck, shoulder, and head pain. There are two types of contraindications in the cervical HVLA OMT, absolute and relative. Absolute contraindications include patients with a medical history of osteoporosis, active osteomyelitis, fractures in the cervical area, severe rheumatoid arthritis, and bone metastasis in the cervical region. Also included are patients with Down syndrome as HVLA therapy can lead to rupture of the transverse ligament of the dens process since this population may have increased laxity of the transverse ligament at baseline (2). 

Cervical HVLA Risks:

There is currently no high quality data to enable accurate estimation of the risk of stroke following cervical spine HVLA thrust techniques. While the data identifies a temporal relationship between cervical spine thrust techniques and stroke, it is possible that in a number of instances the cause of the vertebral artery dissection may have preceded the patient’s attendance for treatment and not be a consequence of the manipulation. While there is a potential for serious sequelae following cervical spine manipulation, the risk appears extremely low. A review of the literature, relating to the risk of neurovascular compromise complicating cervical spine high velocity manipulation, concluded that the risk and benefit analysis supported the continued judicial use of cervical spine HVLA thrust techniques by prudent and appropriately trained practitioners (3). 


Summing up, there is no evidence regarding the unsafety of the HVLA. The key to safety is dependent upon appropriate training, a thorough patient history and a detailed physical assessment prior to the application of any manipulative procedure. Appropriate training in the use of manipulative thrust techniques and subsequent skill refinement through regular practice are considered key elements for safe practice and professional competence. A Cochrane review of manipulation and mobilisation for mechanical neck pain concluded that when combined with exercise, mobilisation and/or HVLA manipulation is beneficial for persistent mechanical neck disorders with or without headache, providing strong evidence for using a multi-modal treatment approach (4). Evidence that other manual interventions have equal or greater efficacy for any given patient presentation is lacking. All interventions that have measurable outcomes have the potential for adverse effects and all practitioners must be cognisant of the requirement for obtaining informed consent prior to the application of any therapeutic intervention and ensure that they operate within the framework of safe and ethical clinical practice.

If you are not sure if you can have a chiropractor or osteopath spine manipulations, book a digital appointment with our experienced physiotherapists to see if you are eligible to receive it, or if there is any contradictions related to your medical history for example, https://mundushealth.com/make-appointments/.


  1. LaPelusa, A., & Bordoni, B. (2023). High Velocity Low Amplitude Manipulation Techniques. In StatPearls. StatPearls Publishing.
  2. Elder, B., & Tishkowski, K. (2022). Osteopathic Manipulative Treatment: HVLA Procedure – Cervical Vertebrae. In StatPearls. StatPearls Publishing.
  3. Rivett, D.A. (1995). Neurovascular Compromise Complicating Cervical Spine Manipulation: What Is The Risk? Journal of Manual & Manipulative Therapy, 3, 144-151.
  4. Gross, A. R., Hoving, J. L., Haines, T. A., Goldsmith, C. H., Kay, T., Aker, P., Bronfort, G., & Cervical overview group (2004). Manipulation and mobilisation for mechanical neck disorders. The Cochrane database of systematic reviews, (1), CD004249.

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